3 edition of Changes in visual discrimination behavior following visual cortex lesions in rabbits found in the catalog.
Changes in visual discrimination behavior following visual cortex lesions in rabbits
Dorothy Tuell Moore
Written in English
|LC Classifications||Microfilm 45811|
|The Physical Object|
|Pagination||vi, 90 l.|
|Number of Pages||90|
|LC Control Number||92895118|
For example, when neuronal responses in posterior cingulate cortex are blocked following fornix lesions, approach/avoidance behavior in rabbits was impaired when subjects were required to use background contextual cues to guide behavior (Smith et al., ). Visual Memory is the ability to take in a visual stimulus, retain its details, and store for later retrieval. Visual Motor Integration is accurate and quick communication between the eyes and hands. Visuocognition is the ability to use visual information to solve problems, make decisions, and complete planning and organizational tasks.
The visual cortex of the brain is that part of the cerebral cortex which processes visual is located in the occipital information coming from the eyes passes through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The part of the visual cortex that receives the sensory inputs from the thalamus is the primary visual cortex, also. Blindsight is the ability of people who are cortically blind due to lesions in their striate cortex, also known as the primary visual cortex or V1, to respond to visual stimuli that they do not consciously see. The majority of studies on blindsight are conducted on patients who have the conscious blindness on only one side of their visual field.
This study examined the strategies used by monkeys lacking striate cortex to perform visual pattern discriminations. Complete bilateral removal of area 17 initially produced severe visual impairment with recovery of even rudimentary visual capacities (e.g., flux discrimination) dependent on gradually retraining the monkeys through a set of increasingly more complex pattern discriminations. The pigmented Long-Evans rat has proven to be an excellent subject for studying visually guided behavior including quantitative visual psychophysics. This observation, together with its experimental accessibility and its close homology to the mouse, has made it an attractive model system in which to dissect the thalamic and cortical circuits underlying visual perception.
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This hypothesis is further reinforced by the fact that rats (1, 5) and rabbits (18), which show no recovery of pattern discrimination following infant visual cortex lesions, also do not show sparing of scattered neurons of the lateral geniculate nucleus following complete striate lesions Cited by: Thus, the rabbits reared in the dark do not exhibit visual discrimination deficits (12) ; striate cortex physiology is essentially normal following early monocular lid suture (19) ; and the restriction of early experience to vertical or horizontal stripes does not change the functional organization of striate cortex neurons (15).Cited by: After bilateral removal of the visual cortex rabbits can still discriminate targets of different brightness, although the threshold is increased In a pilot study it was found that in adult rabbits, after unilateral ablation of the occipital lobe, visual discrimination of brightness performance with the left and right eye was markedly by: 8.
In summary, subject S1 had a profound and persistent deficit in image discrimination, motion discrimination, and orientation discrimination, with complete sparing of a visual approach behavior. This subject had a precise and complete bilateral lesion of V1 (97% of R V1 and 84% of L-V1), as subsequently verified by histology (Figure 4).Cited by: The visual discrimination data are presented in the three sets of graphs in Figs.
3, 4, and 5. The brightness discrimination data are quite consistent for the three subjects. The visual cortex ablation produced a postoperative loss of the habit, but the discrimination could be relearned in slightly more trials than were required by: Following perceptual measurements, ablations were made to selective sites within visual cortex.
Lesions within area 17 or area 18A, including their interface, produced nearly complete impairment of solid line discrimination as well as perceptual grouping at all levels of proximity, whereas lesions to areas 18 or the far lateral extent of area. Lesions of primary visual cortex sustained early in life spare certain aspects of visual processing that can be linked to expansions of bypass pathways to extrastriate cortex.
Recent anatomical studies have revealed strong cerebellar projections into parietal and prefrontal cortex. These findings suggest that the cerebellum might not only play a functional role in motor control but also cognitive domains, an idea also supported by neuropsychological testing of patients with cerebellar lesions that has revealed specific deficits.
The goal of the present study was. Two experiments examined the effects of postoperative haptic discrimination training on the relearning of a maze visual discrimination in rats with visual cortex lesions.
Parameters affecting the loss of ganglion cells of the retina following ablations of striate cortex in primates - Volume 3 Issue 4 - Rosalyn E. Weller, Jon H. Kaas. Further analysis of the visual discrimination deficits following foveal prestriate and inferotemporal lesions in rhesus monkeys.
comp, physiol. Psychol. 76, 1–7 (). Google Scholar. Following perceptual measurements, ablations were made to selective sites within visual cortex. Lesions within area 17 or area 18A, including their interface, produced nearly complete impairment. Lesions of either the superficial layers of the SC or visual cortex also did not completely prevent orienting to very salient, apparently moving visual stimuli, but did produce changes in the.
Patients with IPL lesions demonstrate deficits in visual event discrimination in both visual fields and that often coexist with other visuo-spatial deficits only in the field contralateral to the lesion.
Therefore the bilateral origin of the deficit might distinguish purely visual timing deficits from spatial ones. Furthermore, all our subjects acquired their lesions in later life, thus arguing against substantial rewiring of their visual pathways as has been suggested for subjects with spared blind field visual capacities following surgical removal of a hemisphere as treatment for lesions present at birth or in early infancy (Leh et al., ) or.
Deficits associated with lesions in early visual cortex. The fundamental role of V1 in vision was appreciated early in the last century. Studies in cats, dogs, and monkeys that involved complete lesion of the occipital cortex left animals with little if any visual.
The primary visual cortex (V1) is probably the best characterized area of primate cortex, but whether this region contributes directly to conscious visual experience is controversial.
Finkenstädt, T. & Ewert, J.-P. () Visual pattern discrimination through interactions of neural networks: A combined electrical brain stimulation, brain lesion, and extracellular recording study in Salamandra salamandra.
Journal of Comparative Physiology 99 – [J-PE]. Following habituation to head restraint and training in the visual discrimination task (Figure 1 A), a 3-mm diameter craniotomy was performed over primary visual cortex.
Procedures were similar to headpost surgery except that dexamethasone (8 mg/kg, IM) was also applied. Performance on this second discrimination indicated that animals from all lesion groups had been using visual stimuli based on stripe orientation in the original problem. Members of all lesion groups solved the rotated obliques problem under the transfer condition, though the speed and completeness with which they did so was again inversely.
A recent study in humans ([McDonald et al., ]) found that peripheral, task-irrelevant sounds activated contralateral visual cortex automatically as revealed by an auditory-evoked contralateral occipital positivity (ACOP) recorded from the scalp.
The present study investigated the functional significance of this cross-modal activation of visual cortex, in particular whether the sound.(A and D) Surface view of the cortex indicating extent of the lesion.
(B, C, E, and F) Visual fields represented contralaterally in area 17 (B and E) and in area 18 (C and F), indicating the part.- Task 1: object discrimination. (food always under triangular prism) - Task 2: landmark discrimination.
(food always in the little pot/well close to the cylinder) What part was lesioned - group 1: lesion to inferotemporal cortex (what) - group 2: lesion to posterior parietal cortex - Group 1 monkeys couldn't do task 1 but could do task 2.